Vipersan wrote on Yesterday, 14:10:

Cheers Mr Wierd...I'll look into the things suggested.
All this to get MrBios in the system.
Having had a brief taste of it..I've become fanatical 🤣

I should have some cycles to try to reproduce your issue. I've been largely focused on Win9x. I haven't played much yet with DOS. And when I'm in DOS, I've been using alternate versions of HIMEM. Does your machine boot without HIMEM.SYS? This test could be a way to help narrow-down the nature of your issue.

Also, I tend not to use IDE for hard drives. There aren't many good options for SSD. I've had inconsistent results with CF, with my retro builds. I now use CF only for file transfer. I now use SATA for fixed storage.

This is the motherboard I've been testing with:
https://theretroweb.com/motherboards/s/dfi-586itox

Unfortunately, it's not a very common board. MRBIOS has BIOes for many 430TX boards. You might want to look in that BIOS repository, for either a better fit for your board, or trying another supported board.

-Brian

DaveDDS wrote on 2025-12-09, 04:05:

... My usual approach ... the original ImageDisk system used a 37-Pin 'D' connector ...

Ok, I happened to come across these this morning (while looking for something else of course), and thought it might be a good idea to post them in case anyone wants to better understand which I did to interface to many different floppy drives and types:

On the left is a cable I made up to go inside a system case, and make the changable drive easily accessable via a connector on the back of the system:

You can see a mainboard floppy cable connector at the top, near the middle are 3.5" and 5.25" drive connectors with "twists" around them to make them drive A: and a the bottom a card slot cover with a 37-pin 'D' connector.

Top center is the external cable, with a 'D' connector to fit the one in the system, and a 5.25" floppy connector at the other end (I used 5.25" because thats the most common in vintage systems).

Below that are several adapters I used for various drives:

5.25" -> 3.5"

5.25" -> 8"

5.25 power to 3.5 power (I only brought out one 5.25" extended power cable)

I didn't show the 8" power setup, originally it was a seperate supply as 8" drives need 24v and have a unique connector, but later it was just an external (isolated) 12v supply with a switch to put it in series with the PC 12v.

My power "adapter" which I used for all drives, also had a switch so I could shut off power to the drives completely while changing them. If anyone wants I can post a pic. of it and details on how it's wired.

-- On the right is a cable I made up for a "modern" system which only implemented selects for 1 (A:) floppy driver (who would ever want two floppy drives right!)

You can see at the mainboard end, an add-in reversable small "flying" connector which let me easily swap select and motor-ON between A: (the one that worked) and B: (unimplemented) - this let me make either drive connector A:

Note that I didn't move the "twists" to the center in this case, because I could already make either end drive A:

And... I didn't make this accessable from outside - this was a system I didn't use that much for ImageDisk, and it had an easily removable side cover, so I would just pull off the cover, switch A: to the end of the cable, and attach whatever drive I wanted to use.

Thank you for sharing, Dave! I'm in the market for an 8" floppy drive. Are there any you'd recommend?

-Brian

@Vipersan - you may also want to take a look at your memory settings. HIMEM can get unhappy, if the timings are set too aggressively.

-Brian

bbuchholtz wrote on Yesterday, 18:03:

... I'm in the market for an 8" floppy drive. Are there any you'd recommend? ...

I've mostly settled on a Qume "Qumetrack 242" - This is newer (as 8" drives go) 1/2 height and I've had very good results with it.

I had two of them - but I let one go with the original ImageDisk system - but kept the second because they have worked so well.

I've used older/bigger (like the SA-800) and never found them as easy to work with - the "242" doesn't need a lot of power,
and doesn't need the TG43 signal (ImageDisk has some work-arounds if your drive needs it, but nice to not have to think about it)

I don't recall where exactly I got them , but I can tell you I didn't buy them (either new or used)- a lot of the vintage systems I acquired over the years had "spares" and these were likely just ones that came in and liking the smaller form-factor I gave them a try and liked them!

Awesome - thank you for your recommendations, Dave!

-Brian

bbuchholtz wrote on Yesterday, 18:07:

@Vipersan - you may also want to take a look at your memory settings. HIMEM can get unhappy, if the timings are set too aggressively.

-Brian

Hi Brian ...just for now at least I've refitted the original bios as I still have a lot of floppy disks to process..
I've not given up on MrBios unless I really have to.
I'm wondering if it's possible to flash a larger chip that would hold both bios and have them switched ...sort of bank switching maybe ?
that would at least mean I dont physically have to keep pulling and refitting chips.
A bit like rom switchers in an Amiga.
just a thought..

Forget my silly idea in my last post..
Much more complicated than roms which are only read and not written to.

just ordered a 32 pin <wide> ziff socket..which at least should make swapping out the bios chip less challenging.

Vipersan wrote on Yesterday, 22:23:

Hi Brian ...just for now at least I've refitted the original bios as I still have a lot of floppy disks to process.. I've not gi […]
Show full quote

bbuchholtz wrote on Yesterday, 18:07:

@Vipersan - you may also want to take a look at your memory settings. HIMEM can get unhappy, if the timings are set too aggressively.

-Brian

Hi Brian ...just for now at least I've refitted the original bios as I still have a lot of floppy disks to process..
I've not given up on MrBios unless I really have to.
I'm wondering if it's possible to flash a larger chip that would hold both bios and have them switched ...sort of bank switching maybe ?
that would at least mean I dont physically have to keep pulling and refitting chips.
A bit like rom switchers in an Amiga.
just a thought..

Electronically, you just need one that has twice the expected density, and just put a jumper that feeds a suitable logic level high state on the last address line. (Since it's twice the expected size, there would be more address lines on the chip than on the socket, so it would hang out the back. Put a bodge wire on with a suitable low current 3V source and a jumper, and you have yourself exactly what you want. Jumper on, its the top half of the chip, jumper off, it's the bottom half. Depending on the package though, you might need a suitable conversion board to make sure the pins going to the socket are connected to the correct pins on the chip, though.)

Cheers Mr Wierd...
perhaps not such a silly idea afterall.
😉

Alternatively, and possibly more cleanly...

You install a few sockets on an adapter board, with all the data and address lines shared between them, and then put a suitably large DIP switch on that controls the CS line on each chip, with some sanity checking AND gates to prevent you trying to have two CS high at the same time.

This may be cleaner, as you could then safely* use the in-board rom flashing function.

The only chip that will respond is the one with CS asserted.

*if you intend this, having a CS signal gated latch array to decouple the eeprom when CS is low is a very sensible and sane thing to do. In theory, chips wont let you program them if CS is not asserted. Reality however... may have different outcomes, and hedging the bet is good medicine.

Instead of a single eprom on the socket, you'd have this chip selector board, the latching and sanity logic, lots of sockets, and a DIP switch.

Be mindful that the socket's VCC and GND line are up to the increased load or not, and make appropriate remediation if they are not.

I second the CS method...

-Brian